Majorana protection scaling in quantum-dot Kitaev chains
In plain words
Chains of quantum dots joined by superconductors can be tuned to copy a model wire proposed in 2001 by Alexei Kitaev (a theoretical physicist) that has Majorana modes at its ends, and whether Majorana protection grows quickly with the number of dots decides their usefulness.
Precise statement
For $N$-site Kitaev chains of semiconductor quantum dots coupled through superconducting segments, measure the ground-state splitting $\delta_{E}(N)$ and the parity-qubit coherence time $T_{2}(N)$ under random dot-energy detuning of standard deviation $\sigma$. An answer is the functional form of $\delta_{E}(N)$, testing exponential decay in $N$ at fixed $\sigma/t$ ($t$ the inter-dot hopping).
What would settle it
Spectroscopy and parity-readout coherence measurements on chains with $N = 2 \text{ to at least } 5$.
Status in the literature
Unverified note
Two- and three-site chains (2023-2025), single-shot parity readout of a minimal chain (arXiv:2507.01606, 2025) and a four-site Ge/Si chain probed by a transmon (arXiv:2501.13367, 2025) exist; the scaling of splitting and coherence with N is unmeasured as of 2026.